Vacant land, ownership info?

I’m wondering if anyone has any experience inquiring about ownership info on vacant land that isn’t currently listed for sale (or successfully purchasing such land).

There is a small sliver of land that borders a grassy area next to a public park/parking lot nearby. I always assumed the land was a part of the public park until yesterday when the township came to cut the surrounding grass and cut lean lines on the now apparent property markings (leaving the grass on the sliver of land in question uncut).

The land has never been marked for sale but I assume that it is because the land is pretty much useless for most purposes (small, no direct road access, etc). I’d there a resource for finding ownership info for unlisted land/properties?

Thanks for any help that can be offered!